Pump



July 19% J. M. WEYDELL PUMP Filed April 25, 1940 2 Sheets-Sheet 2INVENTOR. firms-1 UNITED STATES PATENT OFFICE PUMP Jarl M. Weydell,Indianapolis, Ind., assignor of one-half to Edward E. Stout,Indianapolis, Ind.

Application April 25, 1940, Serial No. 331,522

23 Claims.

This invention relates to a pump of the type in which movement of fluidthrough an elastic tube is created by the progression therealong ofmeans which squeezes the walls of the tube together.

It is the object of the invention to improve the construction and. theoperation of such a pump, so that the construction will be simple andinexpensive and will not require the use of valves, and so that inoperation the pumping action will be positive and the pump may be usedeither as a vacuum pump or as a pressure pump.

In accomplishing these objects, the pump is provided with a casing whichhas a cylindrical wall with radial walls at its edges. The flexible tubeis laid against the radially inward surface of the cylindrical wallbetween the radial walls and the outer tube-wall is secured to thatsurface. Inlet and outlet conduits are arranged in communication withthe flexible tube at its ends, and the tube is otherwise closed. Theinner tube-wall is supported by and secured to a circumferential seriesof segmental shoes, which may be mounted together on a supporting ring.An eccentric moves .the shoes successively against the flexible tube sothat the tube is compressed over an area which progresses along thetube, and simultaneously the shoes diametrically opposite from thecompressing shoes are pulled inwardly to open the tube portions withwhich they are associated. The inlet and outlet conduits are arrangedgenerally radially of the casing in such position that their inner endsare closed by the compression of the tube walls. Such conduits arespaced closely enough together and the area of tube compression is madelarge enough to cause the periods during which the respective conduitsare closed to overlap, so that the discharge conduit does not open untilafter the inlet conduit has been closed.

The accompanying drawings illustrate my invention. In the drawings: Fig.1 is a vertical section of a pump embodying my invention, with the fronthalf of the pump casing removed and with part of the flexible tube andof a shoe shown in section; Fig. 2 is a vertical section taken on theline 2--2 of Fig. 1, and showing the pump with the front half of .thecasing and the cover plate in place; Fig. 3 is a front elevation of aportion of the flexible tube; Fig. 4 is a fragmental section on theradial center line of one of the shoes; Figs. 5 and 6 are fragmentalsections of a modification of the pump of Fig. l in which there are twoeccentric rollers, Fig. 6 being taken on the line 66 of Fig. 5; andFigs. 7 and 8 are fragmental sections of another modification of thepump of Fig. 1 in which a single roller rolls against a freeshoe-supporting ring, Fig. 8 being taken on the line 8-8 of Fig. 7.

The pump shown in the drawings has a generally cylindrical casing,conveniently made in two halves. The rear half [0 is arranged to bemounted on a suitable pedestal H and comprises a central bearing sleevel2 to receive the main shaft I3. A flange Id at the front end of thesleeve l2 provides a planar surface l5 of considerable radial extent.Beyond such radial surface l5 the casing extends rearwardly to a radialweb 22 which supports a cylindrical wall IS with a flange l1 at itsfront edge. The front half of the casing consists of a cylindrical walll8 whose inner surface is concentric with the inner surface of the wallI6, and which carries at its rear edge a flange [9, and at its frontedge a web 20 which extends inwardly but which is provided with a largecentral inspection opening closed by a suitable cover plate 2|.

The flexible tube 25 is formed of oval crosssection with ribs 26 and 21on the minor axis of the oval. The outer rib 26 is adapted to be clampedbetween the flanges I1 and IQ of the casing halves by bolts 24, with theouter tubewall against the cylindricalwall |6-I8, and the width of thetube is such that it will be supported in operation by the two radialwebs 20 and 22. Near each end of the tube there is an opening for thereception of a nipple 28, and the ends of the tube are clamped togetherby means of a U-shaped clamp 29, the casing halves being suitably formedto receive the nipples 28 and the clamp 29. The nipples 28 are'circumferentially spaced only enough to leave room for the clamp 29 andthe tube-ends which it embraces. The rib 26 of the flexible tube 25 iscut off so that its ends will abut the conduits 28, and the spacebetween the flanges I! and [9 beyond the conduits 28 is filled by asuitable spacer 3B. Flanges 3| at the inner ends of the nipples 2B clampthe edges of the conduit-receiving holes in the tube 25 against a flatin the cylindrical wall of the casing to seal its edges; the end faceson the flanges 3| being positioned to be engaged by the inner tube-wallwhen the tube 25 is collapsed, to close the nipples 28.

A circumferential series of shoes -3l bear against and support the innertube-wall. These shoes are generally T-shaped in cross-section, and havea cylindrical outer face with a circumferentially extending slot in thecenter thereof for the reception of the inner rib 21 of the tube 25. Therib 21 is secured to each shoe 35-31, as by a single rivet 4| passingthrough alined holes in the walls of the groove 49 and the rib 21 at thecenter of the shoe. The inner ends of each shoe has a foot 42, the heelportion of which provides a bearing surface 43 adapted to bear againstthe planar surface [5 on the rear halfcasing. The feet 42 are ofconsiderable axial ex- .tent and have a cylindrical bearing surface. Inthe pump of Fig. 1, the feet 42 fit against and are supported by thecylindrical surface of a cup 44, which is of Z-shaped cross-section sothat it has an outer flange 45 which overlies the forward ends of thefeet 42, and an inner flange 46 which lies behind the outer race of aball bearing 41 that rolls on the inner surface of the cylindrical walland is mounted on the crank arm 49 carried by the shaft IS. A flangedeccentric sleeve 48 interposed between the ball bearing 41 and the crankarm 49 permits adjustment of the overall eccentricity.

Conveniently, as shown in Fig. 2, the shaft I3 is a hollow shaftsuitably threaded at one end for the reception of a grease cup 50 anddrilled at the other end for the reception of a pressed fit of the shank5| of the crank 49. The shank 5| is desirably drilled with a hole whoseend is only slightly exposed beyond the outer surface of the inner ballrace, and the shaft I3 has a radial hole intermediate its ends, so thatthe hollow shaft l3 may serve as a grease reservoir from which both theball bearing 41 and the bearings for the shaft l3 may be lubricated, thegrease being supplied from the grease cup 50.

The eccentric sleeve 48 between the inner ball race and the crank arm 49is clamped in desired position on the crank arm 49 by the nut 52. Itsfront flange overlies the inner race of the ball bearing 41, and thusholds the outer race against the inner flange 46 of the cup so that thecup through its outer flange 45 holds the shoes in position with theirbearing surfaces 43 against the planar surface 15. The grooves 40 whichreceive the inner ribs 21 of the tube 25 are so positioned with respectto the bearing surfaces 43 that they hold the two ribs 26 and 2'! inradial alinement. In the pump of Figs. 1 and 2, this is accomplished bymaking the flange l1 co-planar with the planar surface l5, and the rearwall of the rib groove 49 co-planar with the bearing surfaces 43.

Desirably, there are a relatively large number of shoes 35--3'|, and Iprefer to use as large a number as is conveniently practical consistentwith economy of manufacture, eight shoes being shown in Figs. 1 and 2.The six shoes 35 are identical, and the other two shoes 36 and 3'! whichengage theends of the tube 25 and which underlie the inlet and outletconduits 28, have adjacent ends of both their outer faces and theirradial surfaces cut away for the reception of a resilient filler block55. I

The shoes 35-3'| are spaced slightly from each other and are yieldinglyheld against the cup 44 by means of a helical spring 56 which overliesthe forwardly extending portions of their feet 42 and lies behind theouter edge of the cupflange 45,

The throw of the crank 49 is sufficient to move the cup and itsassociated shoes out of concentricity with the casing sufficiently tocompletely collapse the flexible tube 25 and to squeeze the tube-wallstogether. The squeeze on the tube walls may be adjusted by turning theeccentric sleeve 48 on the crank 49 to prevent flow of the fluid beingpumped past the point of compression under the pressure at which thepump is to work. A greater working pressure on the fluid than that forwhich the squeeze is adjusted will tend to force fluid past the area ofsqueeze, to limit the working pressure in accordance with the squeezeadjustment and act as a relief for any greater pressure. Adjustment ofthe eccentric sleeve 48 will also increase or decrease thecircumferential extent of the area over which the tubing walls are inengagement, and will likewise increase or decrease the period duringwhich the tube walls are pressed against the respective flanges 3| toclose the nipples 28, to change the time at which the discharge nippleopens with respect to the time at which the inlet nipple closes.

In operation of the pump of Figs. 1 and 2, rotation of the crank shaftl3-49 rolls the outer ballrace around the inner surface of the cup 44 tomove that cup, desirably with little rotation, in a circular orbitaround the axis of the shaft l3. This movement carries the shoes 3lprogressively and successively outward toward the casing at oneprogressing circumferential portion of the cup 44 and inwardly away fromthe casing at the opposite circumferential portion of the cup 44. Thusabout half of the shoes are moving outwardly and half are movinginwardly at all times. Those which are moving outwardly are moving tocompress the tube 25 to force any fluid therein in the direction ofrotation. The last of the outwardly-moving shoes completely collapsesthe tube and squeezes its walls together, to an extent depending on theadjustment of the eccentric sleeve 48, to seal the tube at that pointagainst flow of any fluid in the tube in a direction opposite to that ofrotation.

The shoes which are moving in an inward direction are held against thecup by the helical spring 56 and positively pull the tube to openposition, to draw into the associated portion of the tube a supply offluid through the inlet conduit 28.

I have found that with my segmental shoe construction the severetendency which would otherwise be created to move the inner wall of thetube 25 circumferentially with respect to the outer wall is greatlyreduced, to within a practical limit for long and satisfactoryoperation. I believe the explanation for this is as follows.

During the simultaneous movement of all the shoes they tend to move in acircular orbit, and the group of shoes tends to rotate in a directionopposite to that of the crank shaft. By reason of their separation andthe elasticity of the rib 21 and spring 54 through which they areinterconnected, they are permitted to move in a circumferentialdirection with respect to each other and to the cup 44, to change theclearance space between them. The relative circumferential movement thusprovided changes the shape of the orbit through which they move, todecrease the circumferential component of their movement relative to thepump casing. Moreover, by this movement relative to each other, theymove apart during their outward movement and are spaced apart when theyapproach and pass through the period during which they squeeze thetube-walls together. This is believed to give them a greater effectivecircumferential length substantially equal to the circumferential lengthof the path against which the shoes as a group roll, which permits thegroup of shoes to avoid any backward rotation with respect to the pumpcasing and thus to avoid rubbing the tube-walls against each other andto substantially reduce the circumferential pull on the inner tube wall.

It is to be noted that the cup 44 performs two distinct and separablefunctions: first, it acts as a backing support for the several shoes andprevents their movement inwardly to a position in which they rubtogether and might become wedged together; second, it serves to transmitthe force from the rolling ball-race 41 to the shoes and presents asmooth surface for such race to roll on.

In the pump of Figs. 7 and 8, these two functions are separatelyperformed. The shoe-support is provided by a ring formed with an outerflange Bl overlying the ends of the feet 42, a short axial wall 62against which the feet 42 are held by the spring 56, and an innerannular wall 63 by which the ring is held in place. The wall 63 has acentral opening large enough to avoid interference with the crank 49, orthe flange of the sleeve 48 carried thereby, during its revolution, andis engaged and held rearward by a large washer 54 carried by the crank49 behind the nut at its end. The eccentric roller 4'! rolls against afree race 65 which is of substantially the same outside diameter as thewall 62 of the shoe-supporting ring and is free to movecircumferentially with respect to the shoes and to the shoe support. Ifdesired the race 65 may be the outer ball race of a ball bearing mountedon a crank 49 of suitable throw to give the desired shoe movement.

The pump has no separate valves, for the inner ends of the inlet andoutlet conduits 28 are arranged to be closed by the pressing of theinner j wall of the tube 25 against such inner ends. Desirably, thearrangement is such that the inlet conduit will be closed before thedischarge conduits opens, so that there willbe no loss of eitherpressure or vacuum by any reverse flow through the tube. To this end inthe pump of Figs. 1 and 2, the inlet and outlet conduits 28, althoughdisposed in a generally radial direction, are not precisely radial.Instead, they are inclined away from. each other so that their centerlines cross at a point spaced toward them from the axis of the shaft I3.This spacing is equal to about half the throw of the crank, and islocated in Fig. 1 at the apex of the angle in the section line 22.

Because of this inclination of the conduits 28 the inner wall of thetube 25 does not leave the rearward edge (in the direction of rotation)of the discharge opening to unseal that discharge opening until afterthe portion of the inner wall which is associated with the inlet conduitis pressed against the forward edge of such inlet conduit to completethe closing of that inlet conduit.

This inclination of the nipples 23 has a further function. When thepoint at which the tube 25 is closed approaches the discharge conduit,pressure will be built up at the discharge end of the tube and will tendto force the fluid in the tube past the discharge conduit and into thesmall portion of the tube which lies therebeyond. But the slightinclination of the discharge nipple 28 ly. Thus, during the finalportion of the discharge action the tube is squeezed togethersimultaneously from both ahead and behind the discharge nipple.Similarly, as compression of the tube at the inlet end thereof starts,the filler block 55 first presses together the walls of the tube whichlie between the closed end thereof and the inlet nipple 28.

Where it is not conveniently practical to obtain the desired overlap ofthe closings of the discharge and inlet openings by the arrangement justdescribed, as where the nipples 28 must be spaced apart a distance suchthat the desired or obtainable circumferential length of the area ofsqueeze contact of the tube-walls will not cover both nipples 2Bsimultaneously, and where the slight inclination of the nipples will notovercome the deficiency; the result may be obtained by the modifiedarrangement shown in Figs. 5 and 6.

The pump shown in Figs. 5 and 6 has a casing like that of Figs. 1 and 2save that the planar surface I5 is positioned somewhat rearwardly fromits position in Figs. 1 and 2, and the feet 42 on the shoe segments 65,are of correspondingly greater axial extent, to provide space for tworollers 5'! and 58 in place of the single roller of the modifications ofFigs. 1-2 and 7-8. The two rollers 61 and 68 are shown for simplicity asplain rollers, although in actual practice suitable antifrictionbearings should be provided. The rear roller 58 is mounted on a largeeccentric journal Ill carried by the main shaft H, and has an axialextent of about half the axial width of the feet 42 and behind thecentral plane of the shoes 66. The front roller 51 is mounted on aneccentric 69 which is smaller than the eccentric l0 and is carriedthereby wholly within the circumference of the eccentric 10. Theeccentricity of the cocentric 69 is the same as that of the eccentric 10but its axis is angularly displaced from the axis of the eccentric l'llabout the axis of the main shaft ll so that the point of contact of therollers 61 and 68 are correspondingly displaced from each othercircumferentially of the inner face of the feet 42 of the shoes 66.

In this two roller modification the rollers roll against the inner facesof the feet 42, without the intervening race or cup 44. The shoes aresupported, however, by a ring 6I63 and held against such ring by aspring 56 or by a loosely fitting solid ring (not shown) so that theytend to move in the same way as in other modifications, to causesimultaneous closing of the flexible tube at one side and opening of thetube at the other side. This action is modified, however, by slightmovement of the shoes engaged by therollers B1 and 68 away from the wall62 of the supporting ring, and the tension of the spring 55 (or size ofthe loosely fitting solid ring) is adjusted to permit such separation.The separation of the shoes from the ring (SI-63 which is desirablypermitted is only sufficient to allow the rollers to have someindependent action on the shoes, to create two angularly displacedpoints of pressure at the area over which the tube-walls are squeezedtogether. The squeeze area is thereby extended in circumferentiallength, to cover both the inlet and the outlet ports of the pump.

While this two-roller arrangement does not provide a continuous smoothsurface for the rollers to engage, the variations from smoothness areminimized by the use of the ring 6l63 and the spring 56 or other meansto hold the shoes against excessive separation therefrom; and the effectof such variations on operations is further minimized by the use oflarge rollers 61 and 68 displaced only sufiiciently to provide thedesired extension of the squeeze area.

It will be noted that the tube 25 is supported on all four sides--on itsouter side by the cylindrical wall of the casing, on its inner side bythe shoes 35-3'l, and at its front and rear by the radial walls of thecasing. By reason of this full support for the tube 25 the pressure atwhich the pump may work is increased well beyond what would be possibleif the pressure was held only by the strength of the elastic tube.

The pump may operate in either direction and may be used either as apressure pump or as a vacuum pump. It may be adapted for use with a widevariety of materials. Its flexible tube 25 may be made of rubber or ofany other desirable material which is resistant to any corrosive actionof the material to be pumped. Similarly, the nipples 28 may be made of amaterial which is resistant to attack by the fluid it is desired topump. Thus, by making the tube 25 and nipples 28 of suitable material,the pump may be used for liquids, such as water, acids, oils, gasoline,etc., or for gases.

I claim as my invention:

1. A pump, comprising a casing having a cylindrical inner wall, aflexible tube lying against said casing wall, means securing the outertubewall against said casing wall; a circumferential series ofindividual shoes bearing against the inner tube-wall and securedthereto, means to successively move said shoes to compress said tube andsimultaneously move the diametrically opposite shoes to open said tube,and inlet and discharge ports communicating with said tube at its ends.

2. A pump, comprising a casing having a cylindrical inner wall, aflexible tube lying against said casing wall, means securing the outertube-wall against said casing wall; a longitudinal rib on the innertube-Wall extending radially inward with respect to the casing, and acircumferential series of shoes bearing against the inner tube-wall,embracing said rib, and secured thereto, means to successively move saidshoes to compress said tube, and inlet and discharge ports communicatingwith said tube at its ends.

3. A pump, comprising a casing having a cylindrical inner Wall, aflexible tube lying against said casing wall, a rib on the outertube-wall secured in said casing behind the cylindrical surface thereof;a longitudinal rib on the inner tube-wall extending radially inward withrespect to the casing, and a circumferential series of shoes bearingagainst the inner tube-wall, embracing said rib, and secured thereto,means to successively move said shoes to compress said tube, and inletand discharge ports communi- 1y move said shoes to compress said tube,and inlet and discharge ports communicating with said tube at its ends.

5. A pump, comprising a casing having a cylindrical inner Wall, aflexible tube lying against said casing wall, means securing the outertubewall against said casing wall; a circumferential series of shoesbearing against the inner tubewall and individually secured theretoadjacent to their radial center lines, said shoes being spaced toprovide clearance between them, a backing ring for said shoes, andbearing surfaces on said shoes, means to successively move said shoes tocompress said tube, and inlet and discharge ports communicating withsaid tube at its ends.

6. A pump, comprising a casing having a cylindrical inner wall, aflexible tube lying against said casing wall, means securing the outertubewall against said casing wall; a circumferential series of shoesbearing against the inner tube- Wall and individually secured theretoadjacent to their radial center lines, said shoes being spaced toprovide clearance between them, a backing ring for said shoes, andbearing surfaces on said shoes, means for holding said shoes againstsaid backing ring and means for moving said backing ring eccentri-callyto successively move said shoes to compress said tube and simultaneouslymove the diametrically opposite shoes to open said tube, and inlet anddischarge ports communicating with said tube at its ends.

7. A pump, comprising a casing having a cylindrical inner wall, aflexible tube lying against said casing wall, means securing the outertubewall against said casing wall, a circumferential series of shoesbearing against the inner tubewall and individually secured theretoadjacent to their radial center lines, said shoes being spaced toprovide clearance between them, a backing ring for said shoes, andbearing surfaces on said shoes, and an elastic ring holdingsaid shoesagainst said backing ring, means to successively move said shoes tocompress said tube and simultaneously move the diametrically oppositeshoes to open said tube, and inlet and discharge ports communicatingwith said tube at its ends.

8. The pump as defined in claim 5 in which the backing ring forms a racein engagement with said bearing surfaces and the shoe moving meanscomprises an eccentric operating on said race.

9. The pump as defined in claim 5 in which there is a race fittingagainst said bearing surfaces and said shoe moving means comprises aneccentric operating on said race.

10. The pump as defined in claim 5 in which said shoe moving meanscomprises a plurality of angularly spaced eccentric rollers rollingagainst said bearing surfaces of the shoes, and means for limitingseparation of said shoes from the backing ring.

11. A pump as defined in claim 1, in which the inlet and discharge portsare formed by conduits extending generally radially of the easing andare positioned to be closed by movement of the inner tube-wall againsttheir ends.

12. A pump as defined in claim 1, in which the inlet and discharge portsare formed by conduits extending generally radially of the casing andare positioned to be closed by movement of the inner tube-wall againsttheir ends, the end surface of at least one of said conduits beinginclined from tangential with respect to the casing, whereby the time ofopening of the discharge conduit is delayed with respect to the time ofclosing the inlet conduit.

13. A pump, comprising a casing having a cylindrical inner wall, anelastic tube lying against said wall and secured thereto, inlet anddischarge ports communicating with said tube, a segmented annularstructure engaging the inner tube-wall, means securing the segments ofsaid structure individually to said inner tube-Wall, means for holdingsaid segments in annular relationship and permitting limitedcircumferential relative movement between them, and a rotatableeccentrio acting progressively on said structure to simultaneously closea portion of said tube and open another portion of said tube.

14. A pump, comprising a casing having a cylindrical inner wall, anelastic tube lying against said Wall and secured againstcircumfere'ntial movement with respect thereto, inlet and dischargeports communicating with said tube, a segmented annular structureengaging the inner tube-wall, means for holding said segments in annularrelationship and permitting limited circumferential relative movementbetween them, and an eccentric acting on said structure tosimultaneously close a portion of said tube and permit the diametricallyopposite portion of said tube to open.

15. A pump, comprising a casing having a cylindrical inner wall, anelastic tube lying against said wall and secured thereto, inlet anddischarge ports communicating with said tube, a segmented annularstructure engaging the inner tube-wall, an elastic reinforcement carriedby said inner tube-wall to which the segments of said annular structureare individually secured whereby circumferential stretching of saidreinforcement separates said segments, and a rotatable eccentric actingprogressively on said structure to simultaneously close a portion ofsaid tube and open another portion of said tube.

16. A pump, comprising a cylindrical wall, an elastic tube having onetube-wall in engagement with and secured to said cylindrical wall, portsin communication with said tube, a ring, a series of individual shoescircumferentially movable on said ring and extending therefrom intoengagement with the other tube-wall and secured thereto, and eccentricmeans acting progressively on said ring and shoe structure to close aportion of said tube and simultaneously open another portion of thetube.

17. A pump, comprising a casing having a cylindrical inner wall, anelastic tube lying against said wall and secured thereto, inlet anddischarge ports communicating with said tube, an annular series of shoesengaging and individually secured to the inner tube-wall, said' annularseries of shoes having a normal circumference smaller than thecircumference of a inner tube-wall when said tube is collapsed, saidshoes being yieldingly interconnected and separable from each other attheir periphery an aggregate distance substantially equal to thedifierence between said circumferences and a rotatable eccentric actingprogressively on said annular series of shoes.

18. A pump, comprising a casing having a cylindrical wall, an elastictube lying against said cylindrical wall, an inlet and an outlet portcommunicating with said tubes, tube-supporting radial walls at the edgesof said cylindrical wall, an annular series of individual shoes bearingagainst the free wall of said tube in supporting relationship thereto,and means for moving said shoes successively to compress said tube.

19. A pump as defined in claim 13 with the addition of tube-supportingradial walls at the edges of said cylindrical Wall.

20. A pump, comprising a casing having a cylindrical inner wall, aflexible tube lying against said casing Wall, means securing the outertubewall against said casing wall; a circumferential series ofindividual shoes bearing against the inner tube-wall and securedthereto, means to successively move said shoes to compress said tube andsimultaneously move other shoes to open said tube, and inlet anddischarge ports communicating with said tube at its ends.

21. A pump as defined in claim 20 with the addition of tube-supportingradial walls at the edges of said cylindrical wall.

22. A pump, comprising a cylindrical wall, an elastic tube extendingcircumferentially against said wall, inlet and outlet ports for saidtube, an annular series of separable shoes positioned against said tubeon the opposite side thereof from said cylindrical Wall, and a rotatableeccentric acting progressively on said shoes to cause them to close saidtube.

23. A pump, comprising a cylindrical wall, an elastic tube extendingcircumferentially against said wall, inlet and outlet ports for saidtube, an annular series of separable shoes positioned against said tubeon the opposite side thereof from said cylindrical wall, and a pluralityof rotatable eccentrics acting progressively at circumferentially spacedpoints on said series of shoes to cause said shoes to close the tube.

JARL M. WEYDELL.

